U.S. Pat. No. 4,077,433 to Maldavs illustrates a piston valve arrangement with a passageway through the valve to assist in assuring that the male ball valve remains open in high flow conditions from the male to the female. U.S. Pat. No. 4,881,573 to Durant illustrates a coupler having two poppet valves. The first poppet engages a ball check valve formed in the male coupling and the second poppet is actuated by a manually operated cam. A passageway exists in the piston to allow fluid to be vented or to pressurize the female valve.
U.S. Pat. No. 4,598,896 to Maldavs illustrates a coupler having a spool and a port within the spool. An annular seal is fixedly positioned about the port in the spool. The spool is slidable with respect to the seal which enables pressure to be relieved in the female during coupling and uncoupling with the male. U.S. Pat. No. 4,303,098 to Shindelar discloses a coupler having a female half which includes a female valve having an elongated stem for engaging the male half. The female half of the coupling is vented by a pivotable cam which moves the inner member of the female half to release its locking means and then opens a poppet valve to open the outlet port.
U.S. Pat. No. 4,249,572 to Shindelar et al. discloses a female half which is self-relieving. The female half includes dual poppet valves which are linked together. One of the poppet valves vents the female half of the coupling when the male and female valves are disengaged and uncoupled.
Application Ser. No. 09/037,461 filed by applicant Dennis Zeiber and assigned to Snap-Tite Technologies, Inc., provides a male half of the coupling which pushes the inner body of the pressurized female half of the coupling (which includes a pressurized chamber between a piston and a relief valve positioning member) causing the positioning member to be displaced in a leftward or rearward direction which causes the venting of the female member. The male half of the coupling in application Ser. No. 09/037,461 pulls the inner body of the female half of the coupling rightwardly or forwardly which causes the venting of the female member. The venting occurs when the male and female halves of the coupling are connected or disconnected.
U.S. Pat. No. 5,730,185 to Wilkins et al. discloses a coupling wherein certain positions of the adaptor allow the venting of the dispenser half and the receptacle half. Venting is prohibited by the movement of seals relative to ports and passageways.
U.S. Pat. No. 3,730,221 to Vik provides an exterior vent valve.
None of the related art provides for a metal to metal seal as does the instant invention. Nor does any of the related art provide for a vent comprising a piston having a ball seat and a ball. Nor does any of the related art provide for a piston and a ball vent operable in combination with a pressure source and a stepped bore. None of the related art provides for venting the female half of the coupling continuously when it is separated from the male half of the coupling. Nor does any of the related art provide for low separation force when withdrawing the male from the female. The female valve of the instant invention vents when the relief valve positioning member positions the relief valve in a place within the bore of the body of the female half of the coupler so as to permit room for the ball to lift off its seat upon the application of pressure to the interior of the female half of the coupling.